Plate for a plate kind heat exchanger with asymmetrical corrugations

ABSTRACT

A plate ( 2 ) for a plate kind heat exchanger ( 1 ) is disclosed. The plate ( 2 ) is provided with a plurality of corrugations ( 8 ), a cross-section of the plate ( 2 ) thereby defining a plurality of hills ( 9 ) and valleys ( 10 ) which define flow paths along surfaces of the plate ( 2 ). The hills ( 9 ) and/or the valleys ( 10 ) have a shape which is asymmetrical with respect to a center line ( 11, 12 ) intersecting a top point of the hill ( 9 ) and/or valley ( 10 ). A plate kind heat exchanger ( 1 ) having a plurality of such plates ( 2 ) arranged in a stacked configuration, where the hills ( 9 ) and valleys ( 10 ) formed in the plates ( 2 ) define flow paths between the plates ( 2 ) is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims foreign priority benefits under U.S.C. § 119from Danish Patent Application No. PA202100479, filed May 10, 2021, thecontent of which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a plate for a plate kind heatexchanger. The plate is provided with a plurality of corrugations whichdefine flow paths along opposing sides of the plate. The inventionfurther relates to a plate kind heat exchanger comprising a plurality ofsuch plates.

BACKGROUND

Plate kind heat exchangers comprise a plurality of stacked plates whichare each provided with a corrugated pattern. Thereby flow paths aredefined between the plates, and heat exchange can take place through theplate, between fluids passing along opposing sides of a plate, via therespective flow paths.

The size and shape of the flow paths are determined by the design of thecorrugated pattern of the plates. In a cross-sectional view of one ofthe plates, the corrugated pattern defines hills and valleys, which areoften identical or similar to each other, and thereby define identicalor very similar flow paths along opposing sides of the plate. Moreover,the hills and valleys defined by the corrugated patterns are normallysymmetrical, in the sense that the parts of the plate extending from atop point of a hill or valley are substantially identical in terms ofangle of inclination, radius of curvature, etc.

The plate kind heat exchanger may, e.g., be in the form of a gasket heatexchanger, where the plates are held together under tension in anon-permanent manner, i.e., the plates can be separated from each other.Alternatively, the plate kind heat exchanger may be in the form of abrazed heat exchanger, where tops of the corrugated patterns are brazedor welded to each other, i.e., the plates are joined to each other in apermanent manner.

Identical flow paths along opposing sides of the plates has theconsequence that pressure conditions in fluid flowing in the respectiveflow paths are also identical or very similar. For instance, thepressure drops as the respective heat exchanging fluids pass through theheat exchanger is substantially identical. However, it is sometimesdesirable that the pressure drop of the hot fluid differs from thepressure drop of the cold fluid, in order to obtain a desired heattransfer in the heat exchanger. This could, e.g., be obtained bydesigning the corrugated pattern in such a manner that the hills are notidentical to the valleys. This results in either the hills or thevalleys being relatively large, and this may reduce the strength of theheat exchanger. In order to compensate for this, the thickness of theplates may be increased, at least in the weakened parts, leading topoorer heat transfer through the plates.

SUMMARY

It is an object of embodiments of the invention to provide a plate for aplate kind heat exchanger in which improved heat transfer is obtained inthe heat exchanger.

It is a further object of embodiments of the invention to provide aplate kind heat exchanger with improved heat transfer capability.

According to a first aspect the invention provides a plate for a platekind heat exchanger, the plate being provided with a plurality ofcorrugations, a cross section of the plate thereby defining a pluralityof hills and valleys which define flow paths along surfaces of theplate, wherein the hills and/or the valleys have a shape which isasymmetrical with respect to a center line intersecting a top point ofthe hill and/or valley.

Thus, the first aspect of the invention provides a plate for a platekind heat exchanger, i.e., a heat exchanger comprising a plurality ofstacked plates, as described above. The plate is provided with aplurality of corrugations. Thereby, when plates are stacked to form theplate kind heat exchanger, flow paths are formed along opposing sides ofthe plate, and heat exchange can take place between fluids flowing inthe flow paths formed along opposing sides of the plate. Due to thecorrugations, a cross section of the plate defines a plurality of hillsand valleys, and these hills and valleys define the flow paths on theopposing sides of the plate.

The hills and/or the valleys have a shape which is asymmetrical withrespect to a center line intersecting a top point of the hill and/orvalley.

In the present context the term ‘top point’ should be interpreted tomean a position of a corrugation which constitutes an extremum, in thesense that a distance between the plate material and an average plane ofthe plate is at a maximum.

Since the hills and/or the valleys have a shape which is asymmetricalwith respect to the center line intersecting the respective top point,the shape of the part of the plate in a region approaching one of thetop points from one direction differs from the shape of the part of theplate in a region approaching the top point from an opposite direction.This has the consequence that the flow paths defined by the hills andvalleys of the corrugations are also asymmetrical. Furthermore, theasymmetry has the consequence that the flow paths formed on one side ofthe plate are not identical to the flow paths formed on the oppositeside of the plate. Thereby the pressure conditions prevailing in theheat exchanging fluid flowing along opposing sides of the plate alsodiffer from each other. For instance, the pressure drop of the hot fluiddiffers from the pressure drop of the cold fluid, when passing throughthe heat exchanger, and thereby desired heat transfer between the fluidscan be obtained. Due to the asymmetric hills and/or valleys, this isobtained without significantly weakening the plates, since the hillsand/or valleys are only enlarged on one side. Accordingly, it is notrequired to increase the thickness of the plate in order to compensatefor such a weakening.

Furthermore, when identical plates are stacked to form the plate kindheat exchanger, plates arranged adjacent to each other may be reversedwith respect to each other in the sense that asymmetric hills of oneplate becomes asymmetric valleys of a neighboring plate. Thereby theasymmetric hills and the asymmetric valleys of the respective plates arearranged in abutment, thereby further improving the strength of the heatexchanger.

The hills as well as the valleys may have an asymmetrical shape. As analternative, only the hills may have an asymmetrical shape, while thevalleys have a symmetrical shape, or only the valleys may have anasymmetrical shape, while the hills have a symmetrical shape.

The cross section of the hills and/or valleys may define differentcurvatures at opposing sides of the center line.

According to this embodiment, the asymmetry of the hills and/or valleysis in terms of the curvature of the plate in the region near the toppoint of the hills and/or valleys, i.e., the curvature of a pathfollowed by the plate material in the region of the top point, withinthe cross section of the plate. For instance, a radius of curvature ofthe plate material may differ from one side of the center line to anopposite side of the center line.

Alternatively, or additionally, a distance along a surface of the platebetween a top point of a hill and a top point of a first neighboringvalley may differ from a distance along the surface of the plate betweenthe top point of the hill and a top point of a second neighboringvalley.

In the corrugated pattern, the hills and valleys are arrangedalternatingly, in the sense that a given hill is arranged between twovalleys and a given valley is arranged between two hills, except forhills or valleys which are arranged at an outer boundary of thecorrugated pattern. Such hills/valleys will only have one neighboringvalley/hill.

The plate material interconnects the top points of hills and valleyswhich are positioned adjacent to each other, i.e., neighboring hills andvalleys. According to this embodiment, the asymmetry of a given hill isin the form of differences in the distance, along the surface of theplate, to the neighbouring valleys arranged adjacent to the hill onopposing sides of the center line intersecting the top point of thehill. The difference in distance may, e.g., be caused by a difference inslope of the respective parts of the plate.

It should be noted that, even though the embodiment described aboverefers to the distance between a top point of a hill and the respectivetop points of neighboring or adjacent valleys, the above descriptionalso applies to a reversed situation, i.e., to distances between a toppoint of a valley and the respective top points of neighboring oradjacent hills.

The hills and valleys may form a herring bone pattern on the plate.According to this embodiment, the top points of the hills and valleysextend along substantially linear lines along the surfaces of the plate,and lines formed on opposing halves of the surfaces form an angle withrespect to each other. When stacking the plates in order to form theplate kind heat exchanger, the plates may be arranged in such a mannerthat adjacent plates are reversed with respect to each other. Therebythe lines defined by the hearing bone pattern on adjacent plates willnot coincide, but will instead intersect each other at a number ofintersection points. Fluid flowing through the flow paths definedbetween the plates by the corrugations is thereby forced to changedirection, thereby causing turbulence in the fluid which providesimproved heat transfer.

The asymmetry of a given hill and/or valley may vary along a directionin which the hill and/or valley extends.

According to this embodiment, the asymmetry of the hills and/or valleys,is not constant along the direction in which the respective hills and/orvalleys extend. The variation in asymmetry may, e.g., be in terms of themagnitude of the asymmetry, i.e., how much the shape of the hill orvalley at one side of the center line intersecting the top point differsfrom the shape of the hill or valley at a second, opposite, side of thecenter line.

Furthermore, the asymmetric shape may shift from one side of the centerline to the other. For instance, in the case that the asymmetry definesdifferent curvatures at opposing sides of the center line, a firstradius of curvature, R1, may be defined at a first side of the centerline, and a second radius of curvature, R2, may be defined at a second,opposite, side of the center line, at a given position along thedirection in which the hill or valley extends. However, at anotherposition along this direction, the second radius of curvature, R2, maybe defined at the first side of the center line, and the first radius ofcurvature, R1, may be defined at the second side of the center line.

The variations in asymmetry may be smooth and continuous. Alternatively,or additionally, abrupt changes in the asymmetry may occur at specificpositions along the direction in which the hill or valley extends.

Due to the variations in asymmetry, the turbulence in the fluid flowingthrough the resulting flow paths is increased, thereby improving theheat transfer.

Furthermore, when stacking the plates in order to form the plate kindheat exchanger, the variations in asymmetry of adjacent plates can bearranged relative to each other in a manner which improves the strengthof the plate kind heat exchanger. This allows the plates to bemanufactured with a lower thickness, or at least without increasing thethickness, without compromising the strength of the heat exchanger. Thelower thickness of the plates even further improves the heat transferthrough the plate.

Finally, the variations in asymmetry provides a better locking orfixation of the plate during pressing when manufacturing the plate.Thereby the plate can be manufactured in a more accurate manner. This,in turn, results in a more uniform thickness of the plate and improvedcontact between the plates when they are stacked under tension, in thecase that the plate kind heat exchanger is in the form of a gasket heatexchanger. Similarly, in the case that the plate kind heat exchanger isin the form of a brazed heat exchanger, contact between the plates isalso improved.

The variation in asymmetry may be periodic. According to thisembodiment, the plates can suitably be stacked in a manner which ensuresthat specific sections of the hills or valleys of adjacent plates are incontact.

According to a second aspect the invention provides a plate kind heatexchanger comprising a plurality of plates according to the first aspectof the invention arranged in a stacked configuration, wherein the hillsand valley formed in the plates define flow paths between the plates.

Since the plate kind heat exchanger comprises a plurality of platesaccording to the first aspect of the invention, the remarks set forthabove with reference to the first aspect of the invention are equallyapplicable here.

In particular, in the case that the asymmetry of the hills and/orvalleys varies along the direction in which the hills and/or valleysextend, the plates may be stacked in the manner described above, therebyimproving the strength of the heat exchanger and improving the heattransfer.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in further detail with reference tothe accompanying drawings in which

FIG. 1 is a perspective view of a plate kind heat exchanger according toan embodiment of the invention,

FIG. 2 illustrates four plates for a plate kind heat exchanger accordingto an embodiment of the invention,

FIG. 3 is a cross-sectional view of part of a plate for a plate kindheat exchanger according to an embodiment of the invention,

FIG. 4 is a perspective view of part of a plate for a plate kind heatexchanger according to an embodiment of the invention,

FIG. 5 is a top view of the plate for a plate kind heat exchanger ofFIG. 4, and

FIG. 6 is a schematic view of a plate for a plate kind heat exchangeraccording to an embodiment of the invention.

DETAILED DESCRIPTION

FIG. 1 is a perspective view of a plate kind heat exchanger 1 accordingto an embodiment of the invention. The plate kind heat exchanger 1comprises a plurality of plates 2 arranged in a stack between two endplates 3. A first fluid inlet 4 is connectable to a fluid source of afirst heat exchanging fluid, and a second fluid inlet 5 is connectableto a fluid source of a second heat exchanging fluid. Heat exchangingfluids thereby enter the plate kind heat exchanger 1 via the respectivefluid inlets 4, 5, and pass along opposing sides of respective plates 2,while heat exchange takes place through the plates 2. The first heatexchanging fluid exits the plate kind heat exchanger 1 via a first fluidoutlet 6, and the second heat exchanging fluid exits the plate kind heatexchanger 1 via a second fluid outlet 7.

FIG. 2 illustrates four plates 2 for a plate kind heat exchanger, e.g.,the plate kind heat exchanger illustrated in FIG. 1. The plates 2 areshown in an exploded manner, i.e., with a distance between the plates 2.However, in order to form a plate kind heat exchanger by means of theplates 2, the plates 2 are stacked, i.e., arranged immediately adjacentto each other, with their surfaces completely overlapping. Thereby thefluid inlets 4, 5 and the fluid outlets 6, 7 are also arranged adjacentto each other, thereby forming inlet manifolds and outlet manifoldswhich distribute the heat exchanging fluids to flow paths formed betweenthe plates 2.

Each of the plates 2 is provided with a plurality of corrugations 8defining hills and valleys which are arranged in a herring bone patternon the plate 2. The herring bone patterns are arranged in such a mannerthat their directions alternate from one plate 2 to the plates 2arranged adjacent thereto. At positions where hills of adjacent plates 2coincide, the plates 2 abut each other. Thereby flow paths are definedalong the surfaces of the plates 2, and these flow paths ensure thatturbulence is introduced in the fluid flowing therein, thereby ensuringa good heat exchange between heat exchanging fluids flowing alongopposing sides of a given plate 2.

FIG. 3 is a cross-sectional view of a part of a plate 2 for a plate kindheat exchanger according to an embodiment of the invention. The plate 2is provided with a corrugated pattern 8 defining a plurality of hills 9and valleys 10. In FIG. 3, two hills 9 and two valleys 10 are shown. Afirst heat exchanging fluid may pass along a first surface of the plate2 in the cavities defined by the hills 9, and a second heat exchangingfluid may pass along a second, opposite, surface of the plate 2 in thecavities defined by the valleys 10. Accordingly, the hills 9 and valleys10 of the corrugated pattern 8 define flow paths along the surfaces ofthe plate 2, and heat exchange can take place between the first heatexchanging fluid and the second heat exchanging fluid, through the plate2.

The hills 9 have a shape which is asymmetric with respect to a centerline 11 intersecting a top point of the hill 9, in the sense that aradius of curvature, R1, of the part of the hill 9 arranged to the leftof the center line 11, is smaller than a radius of curvature, R2, of thepart of the hill 9 arranged to the right of the center line 11. Thisfurther has the consequence that the distance along the surface of theplate 2 from the top point of the hill 9 to the top points of respectiveneighboring valleys 10 differ from each other. Accordingly, the distancefrom the top point of the hill 9 to the top point of the valley 10arranged to the left of the hill 9 is shorter than the distance from thetop point of hill 9 to the top point of the valley 10 arranged to theright of the hill 9.

Furthermore, the valleys 10 also have a shape which is asymmetric withrespect to a center line 12 intersecting the top point of the valley 10,in the sense that distance to the top points of the neighboring hills 9differ from each other, similar to the situation described above.Furthermore, the valleys 10 define a radius of curvature, R3, whichdiffers from the radii of curvature, R1 and R2, defined by the hills 9.

Due to the asymmetric shapes of the hills 9 and valleys 10, the flowpaths defined by the hills 9 and the valleys 10 are also asymmetrical,and the flow paths defined along the respective opposing sides of theplate 2 are not identical to each other. Thereby the pressure conditionsprevailing in the first and second heat exchanging fluids flowing alongthe opposing sides of the plate 2 also differ from each other, therebyallowing desired heat transfer between the fluids to be obtained.

FIG. 4 is a perspective view of part of a plate 2 for a plate kind heatexchanger according to an embodiment of the invention. The plate 2 ofFIG. 4 could, e.g., be the plate 2 illustrated in FIG. 3.

In the plate 2 illustrated in FIG. 4, the asymmetry of the hills 9 andvalleys 10 is not constant along a direction, illustrated by arrow 13,along which the hills 9 and valleys 10 extend. Instead, the asymmetryshifts from side to side, thereby defining shoulders 14. The shifts may,e.g., cause the radii of curvature, R1 and R2, to switch place in thesense that the first radius of curvature, R1, moves from the left sideof the center line to the right side of the center line and back again,while the second radius of curvature, R2, moves from the right side ofthe center line to the left side of the center line, and back again. Thechange in the asymmetry along the direction 13 is substantiallyperiodic.

These variations in the asymmetry along direction 13 forces the heatexchanging fluids flowing along the respective flow paths along thesurface of the plate 2 to change direction, thereby causing theturbulence in the heat exchanging fluids to increase. Thereby the heattransfer between the fluids is improved.

Furthermore, when the plate 2 is stacked with other plates in order toform the plate kind heat exchanger, the variations in asymmetry ofadjacent plates 2 can be arranged relative to each other in a mannerwhich improves the strength of the plate kind heat exchanger. Thisallows the plates 2 to be manufactured with a lower thickness, withoutcompromising the strength of the plate kind heat exchanger. The lowerthickness of the plates 2 even further improves the heat transferthrough the plates 2.

Finally, the variations in asymmetry provides a better locking orfixation of the plate 2 during pressing when manufacturing the plate 2.Thereby the plate 2 can be manufactured in a more accurate manner. This,in turn, results in a more uniform thickness of the plate 2 and improvedcontact between the plates 2 when they are stacked under tension.

FIG. 5 is a top view of the plate 2 of FIG. 4. Only part of the plate 2is shown. It can clearly be seen how the shoulders 14 are shifting fromside to side along the direction 13 in which the hills 9 extend. It canfurther be seen that the shoulders 14 causes the resulting flow pathsalong the plate 2 to have a curvy shape which forces the heat exchangingfluids flowing therein to change direction, thereby increasing theturbulence in the fluids.

FIG. 6 is a schematic view of a plate 2 for a plate kind heat exchangeraccording to an embodiment of the invention. The plate 2 is providedwith a plurality of corrugations 8 defining a plurality of hills 9 andvalleys 10 forming a herring bone pattern.

It can be seen that the hills 9 form shoulders 14 in the mannerdescribed above with reference to FIG. 4. Accordingly, the asymmetry ofthe hills 9 varies along the direction in which the hills 9 extend.

While the present disclosure has been illustrated and described withrespect to a particular embodiment thereof, it should be appreciated bythose of ordinary skill in the art that various modifications to thisdisclosure may be made without departing from the spirit and scope ofthe present disclosure.

1. A plate for a plate kind heat exchanger, the plate being providedwith a plurality of corrugations, a cross section of the plate therebydefining a plurality of hills and valleys which define flow paths alongsurfaces of the plate, wherein the hills and/or the valleys have a shapewhich is asymmetrical with respect to a center line intersecting a toppoint of the hill and/or valley.
 2. The plate for a plate kind heatexchanger according to claim 1, wherein the hills as well as the valleyshave an asymmetrical shape.
 3. The plate for a plate kind heat exchangeraccording to claim 1, wherein the cross section of the hills and/orvalleys define different curvatures at opposing sides of the centerline.
 4. The plate for a plate kind heat exchanger according to claim 1,wherein a distance along a surface of the plate between a top point of ahill and a top point of a first neighboring valley differs from adistance along the surface of the plate between the top point of thehill and a top point of a second neighboring valley.
 5. The plate for aplate kind heat exchanger according to claim 1, wherein the hills andvalleys form a herring bone pattern on the plate.
 6. The plate for aplate kind heat exchanger according to claim 1, wherein the asymmetry ofa given hill and/or valley varies along a direction in which the hilland/or valley extends.
 7. The plate for a plate kind heat exchangeraccording to claim 6, wherein the variation in asymmetry is periodic. 8.The plate kind heat exchanger comprising a plurality of plates accordingto claim 1 arranged in a stacked configuration, wherein the hills andvalleys formed in the plates define flow paths between the plates.